Decrease in spectral entropy by low tidal volume ventilation-associated severe hypercapnia: a case report.

Severe hypercapnia can be predicted by a decrease in cerebral electrical activity. The authors describe a sudden decrease in spectral entropy due to severe hypercapnia-induced respiratory acidosis in a patient with chronic pulmonary obstructive disease during lung resection. After two and a half hours of low tidal volume ventilation in the lateral position, the state entropy suddenly dropped from 45 to 7, without any changes in the effect-site concentration of propofol, end-tidal carbon dioxide (CO2) tension, oxygen saturation, or arterial pressure. However, arterial blood gas analysis showed severe respiratory acidosis (pH 7.01, PaCO2 115 mmHg and PaO2 246 mmHg with FIO2 of 0.5). Immediate hyperventilation improved the state entropy and acid-base balance. Electroencephalography-based spectral entropy can detect severe hypercapnia in chronic pulmonary obstructive disease patients with a large arterial to end-tidal CO2 difference due to prolonged hypoventilation during thoracic surgery.

Effects of different dosages of oxycodone and fentanyl on the hemodynamic changes during intubation.

OBJECTIVES: To investigate the effectiveness of oxycodone compared with fentanyl for attenuating the hemodynamic response during endotracheal intubation. METHODS: This study was conducted from June 2014 to February 2015 on healthy adults undergoing general anesthesia at the Yeungnam University Hospital, Daegu, Republic of Korea. Ninety-five patients were randomly assigned to one of 3 groups to receive the following drugs; Group F: fentanyl 2 µg/kg; Group O/70: oxycodone 140 µg/kg; Group O/100: oxycodone 200 µg/kg. Five minutes after injection of the study drug, general anesthesia was induced with propofol 1.5 mg/kg and rocuronium 0.8 mg/kg. The mean blood pressure (MBP), heart rate (HR), peripheral oxygen saturation (SpO2), and bispectral index (BIS) were compared before administration of the study drug (T1), just before endotracheal intubation (T2), one minute after endotracheal intubation (T3), and 7.5 minutes after endotracheal intubation (T4). Complications were assessed. RESULTS: The 2 oxycodone groups showed no significant differences in MBP, HR, SpO2, and BIS compared to Group F at the time points assessed. The incidence of complications was comparable among the groups.  CONCLUSIONS: Oxycodone could successfully be used to attenuate the sympathetic response during anesthetic induction. The hemodynamic profiles and incidence of complications were clinically similar among the groups, but Group O/70 tended to show a lower rate of complications of apnea.